Radiation Oncology Department, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Int J Radiat Oncol Biol Phys. 2011 Sep 1;81(1):305-12. doi: 10.1016/j.ijrobp.2010.11.019. Epub 2011 Jan 13.
To provide quantitative information on the image registration differences from multiple systems for image-guided radiotherapy (IGRT) credentialing and margin reduction in clinical trials.
Images and IGRT shift results from three different treatment systems (Tomotherapy Hi-Art, Elekta Synergy, Varian Trilogy) have been sent from various institutions to the Image-Guided Therapy QA Center (ITC) for evaluation for the Radiation Therapy Oncology Group (RTOG) trials. Nine patient datasets (five head-and-neck and four prostate) were included in the comparison, with each patient having 1-4 daily individual IGRT studies. In all cases, daily shifts were re-calculated by re-registration of the planning CT with the daily IGRT data using three independent software systems (MIMvista, FocalSim, VelocityAI). Automatic fusion was used in all calculations. The results were compared with those submitted from institutions. Similar regions of interest (ROIs) and same initial positions were used in registrations for inter-system comparison. Different slice spacings for CBCT sampling and different ROIs for registration were used in some cases to observe the variation of registration due to these factors.
For the 54 comparisons with head-and-neck datasets, the absolute values of differences of the registration results between different systems were 2.6±2.1 mm (mean±SD; range 0.1-8.6 mm, left-right [LR]), 1.7±1.3 mm (0.0-4.9 mm, superior-inferior [SI]), and 1.8±1.1 mm (0.1-4.0 mm, anterior-posterior [AP]). For the 66 comparisons in prostate cases, the differences were 1.1±1.0 mm (0.0-4.6 mm, LR), 2.1±1.7 mm (0.0-6.6 mm, SI), and 2.0±1.8 mm (0.1-6.9 mm, AP). The differences caused by the slice spacing variation were relatively small, and the different ROI selections in FocalSim and MIMvista also had limited impact.
The extent of differences was reported when different systems were used for image registration. Careful examination and quality assurance of the image registration process are crucial before considering margin reduction using IGRT in clinical trials.
为了在临床试验中为图像引导放疗（IGRT）认证和减少边缘提供有关来自多个系统的图像配准差异的定量信息。
来自三个不同治疗系统（Tomotherapy Hi-Art、Elekta Synergy、Varian Trilogy）的图像和 IGRT 移位结果已从不同机构发送到图像引导治疗质量保证中心（ITC），以供放射肿瘤学组（RTOG）试验评估。比较中包括 9 名患者数据集（5 名头颈部和 4 名前列腺），每个患者有 1-4 个每日个体 IGRT 研究。在所有情况下，通过使用三个独立的软件系统（MIMvista、FocalSim、VelocityAI）重新对计划 CT 与每日 IGRT 数据进行重新配准，重新计算了每日移位。在所有计算中都使用了自动融合。将结果与机构提交的结果进行了比较。为了进行系统间比较，在注册中使用了相似的感兴趣区域（ROI）和相同的初始位置。在某些情况下，由于这些因素，使用了不同的 CBCT 采样切片间距和不同的 ROI 进行注册，以观察注册的变化。
对于 54 个头颈部数据集的比较，不同系统之间的配准结果差异的绝对值为 2.6±2.1mm（均值±标准差；范围 0.1-8.6mm，左右[LR]）、1.7±1.3mm（0.0-4.9mm，上下[SI]）和 1.8±1.1mm（0.1-4.0mm，前后[AP]）。对于前列腺病例的 66 次比较，差异为 1.1±1.0mm（0.0-4.6mm，LR）、2.1±1.7mm（0.0-6.6mm，SI）和 2.0±1.8mm（0.1-6.9mm，AP）。切片间距变化引起的差异相对较小，FocalSim 和 MIMvista 中的不同 ROI 选择也有一定的影响。
报告了使用不同系统进行图像配准时的差异程度。在临床试验中考虑使用 IGRT 减少边缘之前，必须仔细检查和保证图像配准过程的质量。
